1. Field of the Invention
The present invention relates to a current sensor capable of measuring, in a non-contact manner, a current flowing through a conductor, and particularly relates to a current sensor that detects a magnetic field generated by a current and measures a current value.
2. Description of the Related Art
A current sensor capable of measuring a current value in a non-contact manner on the basis of an induction field generated by a measured current, has been put to practical use. The current sensor includes a magnetoelectric transducer for detecting an induction field, and calculates a current value of a measured current on the basis of the intensity of a magnetic field detected by the magnetoelectric transducer. For example, a Hall element which converts the intensity of a magnetic field into an electrical signal using a Hall effect, a magnetoresistance effect element which uses a change in an electrical resistance value by a magnetic field, or the like is used as the magnetoelectric transducer.
A non-contact type current sensor may be used, for example, for measuring a current flowing through an inverter for motor driving. Currents of a plurality of phases flow through the inverter. Thus, to achieve high current measurement accuracy in this use, it is necessary to appropriately eliminate influence of an induction field generated by a current of another phase. For such a purpose, a current sensor has been proposed which has a configuration in which a plurality of conductors forming current paths are arranged within a single plane and a magnetic sensor is arranged symmetrically to the plane (e.g., see U.S. Patent Application Publication No. 2007/0096716).
In the above-described current sensor, the magnetic sensor is arranged such that the magnetic sensor is unlikely to be influenced by an induction field generated by a current of another phase, and thus current measurement accuracy is maintained to some extent. However, to achieve sufficiently high current measurement accuracy, it is necessary to arrange the magnetic sensor such that the magnetic sensor is tilted relative to the current paths, but this arrangement is not realistic in terms of mounting accuracy and manufacturing cost.
The present invention has been made in view of such a point and provides a current sensor having a simple structure which is able to eliminate influence of an induction field generated by a current flowing through an adjacent conductor.